First, pat both sides of the fillets with a paper towel. This will help reduce splatter while cooking. Next, lightly sprinkle each side with salt, pepper, garlic powder, and onion powder.
Now, melt butter in a pan over medium heat. When the butter starts to bubble a bit, add the fillets, SKIN SIDE UP, and slow simmer for 3-4 minutes. Flip fish over and cook for another 3-4 minutes.
Remove the fish from the pan and set aside. Now it's time to make the lemon caper butter sauce! Add the remaining butter, lemon juice, capers (drained), and parsley flakes.
Slow simmer for about 30 seconds, then return the fish to the pan. Spoon the lemon butter caper sauce over the fish and heat just until hot - about 30 seconds.